Electrolytic cell



Patented Dec. 3, 1929 UNITED STATES RUBERT EDGEWORTH-JOHNSTONE, FLONDON, ENGLAND ELECTRDLYTIC CELL Application lled January 10, 1929,Serial No. 331,506, and in Great Britain November 4,1192?.

'lhis invention relates to electrolytic cells and has particularreference to a bi-polar electrolytic cell and has for its object toprovide an improved form of electrolytic apparatus or cell particularlyadapted for the electro-deposition of metals from solutions or theirsalts. y

ln the general construction of bi-polar electrolytic cells it iscustomary to provide a series of'electrodes located side by side andimmersed in the electrolyte to be treated.

The present invention comprises a bi-polar electrolytic cell forelectrodeposition of metals from solutions of their salts consisting ofa number of closely positioned electrodes in the torni of sheets orplates, normally insoluble and upon which metal israpable of beingdeposited, said plates being held together in pack formationY and promyvided with` apertures or perforations enabling electrolyte to be passedthrough the channels afforded by said perforations.

'lhe provision for circulation of electrolyte between the electrodesaccording to the present invention enables, in addition to a decrease inresistance, higher current density to be obtained vvith a given voltagethan is possible in customary types of cell, still further reducing thesize of the unit for a given im output. Moreover a considerable relativevelocity between electrolyte and electrodes is tound to be trequentlybeneficial in the electrodeposition ot metals.

rUne convenient arrangement in conformity vvith the invention maycomprise as electrodes a number ot metal plates of any suitable shapeandseparated by electrically insulating packing pieces. lhe electrodesand packing pieces are held together in a preter`- au ably horizontallylocated A.trame by means oiE any convenient lorm ot .screvv or othermechanism so that the assembled'electrodes and lramevvorlr resemble inappearance a dlterpresa llhe electrodes are perforated in acre cordancewith the manner in `which it is de sired to circulate electrolytebetween them. ller instance? by suitably pertorating the plates andpacking pieces, electrolyte entering through the inlet passage may bemade to pass between every alternate pair ot plates to the further endof the pack, returning be tween the remaining pairs of plates. This andother variations of the path of the electrolyte through the cell may beadopted in order to secure a suitable velocity of. circulation orcontrol of the temperature in the cell. Where it is desired to keepseparate the electrolyte in contact with the anode and cathode surfacesrespectively a porous diaphragm suitably perforated to allow forcirculation of the electrolytes and having a packing piece on eitherside of it may be interposed between each pair of plates.

Thus in one possible arrangement each alternate electrode from one endof the apparatus may have one or more perforations near the bottomthereof, While the other interposed alternate plates are provided withperforations near the upper end. In another arrangement each electrodeis provided with top and bottom perforations with the exception of theend electrodes which communicate respectively with an inlet forelectrolyte.

Electrolyte may be circulated through the cell by means ot a suitablepump connected to either the inlet or outlet of the cell.

In the preferred form, however, circulation is established Without theuse of a Inechanical pump by causing pipes from both the inlet andoutlet of the cell to communicate with an elevated storage tank, andarranging for any gases evolved during electrolysis to aerate theascending column b electrolyte contained in the outlet pipe. uchcirculation by aeration ot'the ascending column is assisted by theheating effect etn the electric current on both gases and electrolytevvhile passing through the cell..

Where that method of circulation is employed in which successiveelectrodes are pertorated alternately at the top and bottom., thoseelectrodes perforated near the bottom end may have also a smallpert'oration near the top. Gases evolved betvveen the electrodes maythen rise to the top and pass through large and small perllorationsalter neitely direct to the outlet passage 'vvithout again minglingvvith the circulating electrolyte. At the outlet trom the cell bothelectrolyte and gas may be dravvn o through lili the same passage, or aseparate outlet at the top of the end plate may be provided for the gas,which may be subsequently introduced into the ascending column ofelectrolyte in anyconvenient manner. Alternatively all the electrodesmay have above the level of the upper perforation for the passage ofelectrolyte, small openings which form a direct passage for the evolvedgases along the top of the cell to the outlet.

The elevated storage tank may embody means for cooling the electrolyteso as to regulate the temperature at which it enters the cell, and wherethe electrolyte contains volatile constituents the tank may be totallyenclosed and arrangements made to recover any volatile constituentpresent in the evolved gas before discharging the latter into theatmosphere.

The electrodes themselves are bi-polar and work in series, those ateither end being connected to a suitable supply of direct current.Furthermore they may be of any desired shape and constructed of anysuitable material or combination of materials according to the nature ofthe solution to be electrolyzed, the metal being deposited upon thesurface of the electrodes in layer formation, while apart from theinterposed insulating packing pieces they may be provided with maskedareas. This may be accomplished by varnishing or treating euivalentlythe portions of the plates remote rom the centres so that the electricalresistance of the leakage path is very much greater than that by way ofthe electrodes.

In order that the invention may be more readily understood reference isdirected to the accompanying drawings wherein Figure 1 is a general sideelevational view of a preferred construction of cell shown assembled,

Figure 2 illustrates a form of plates or electrodes and gaskets whichwhen assembled form a cellof the type shown by Figure 1,

Figure 3 represents a diagrammatic sketch showing the respectivedirections of flow of the liquid and the gas within a cell, asillustrated by Figure 1,

Figures 4 and 5 illustrate 'in diagrammatic form two types showing thedirection of the flow of the electrolyte,

Figure 6 is an illustration of the arrangement of plate electrodesadapted when assembled for use to enable the cell to work upon theparallel flow principle, while Figure 7 is a. plan view showing indetail the components of a diaphragm cell having provision forcountercurrent flow.

Referring now to these drawings and initially to the form of cellillustrated by Figure 1 the numeral 2 designates the'base of a stand orstructure 3 of suit-able shape adapted to receive and support in packformation a series of plate electrodes such for instance as the kind.shown in Figures 2, 6 or 7. In Figure 1 the pack of electrodes isrepresented generally by 4 while the means by which the individualelements of the pack are held in position consists of a hand adjustablescrew 5 operating in well known manner to compress or release pressureupon the pack elements themselves. An inlet pipe 6 is provided for thepack 4 while outlet occurs by way of a pipe 7 these two pipe connectionsbein associated with a pump for circulation of e ectrolyte through thecell if desired, but according to the preferred arrangement illustratedby Figure 1 circulation is established without the use of a mechanicalpump by causing the pipes 6 and 7 to communicate with an elevatedstorage tank (not shown) and arranging for any gases evolved duringelectrolysis to aerate an ascending column of electrolyte contained inthe outlet pipe 7. For this purpose any suitable form of aerating device8 is provided havin a connection at its lower end to the outlet pipe 7and a branch connection to an outlet pipe 9 for gas evolved with thecell. In this method of circulation the arrangement of electrodes asshown in Figure 2 is employed. The electrodes comprise plates A and Bhaving an intermediate packing piece C the arrangement being repeated inorder for as many electrodes as the cell is intended to comprise. Everyelectrode A is, according to the arrangement illustrated, provided witha lower erforation a while the alternate electrodes are provided with anupper perforation b. Moreover the electrodes A are provided with a smallupper perforation c so that gases evolved between the electrodes maythen rise to the top and ass through large and small perforationsalternately direct to the outlet passage this condition of affairs beingshown diagrammaticall by Figure 3 where :v designates the path of ow ofelectrolyte and y the path of the gas according to the arrangement shownby Figure 2.

In Figures 4 and 5 are illustrated in diagrammatic form three differentways respectively in which the electrolyte may be caused to flow throughthe cell. Figure 4 illustrates a series arrangement of flow for theelectrolyte, each alternate plate being provided with a perforationeither at the to or at the bottom. In Figure 5 a compoun series paralleltiow arrangement is provided for, wherein groups of two plates arearranged to enable parallel flow for each individual group while thesaid groups are arranged for the flow to occur inseries as shown inFigure 6.

Figure 6 represents individual plate electrodes and packing pieces whichalthough shown of rectangular shape may be of any form desired, saidelements being ada ted to be assembled and enable the electrolyte toflow in parallel but along staggered passages to reduce leakage. In thisfigure the numeral Ill) till

meeste 10 designates one plate having holes 10- and 10b located near theend of one diagonal, an intermediate packing piece 11 it then assembledadjacent the plate 10 while the next plate 12 is provided with holes 12aand 12 located near the end o a diagonal differentv trom that of theplate 10. A further packing Apiece 13 is located adjacent theplate 12and this arrangement may be repeate elements as desired.

`According to a further modified arrangement as shown in Figure 'I thecell is embodled with elements enabling a countercurrenty How of theelectrolyte to take place. In this example 14 represents oneplatelelectrode the negative signs represent the liow of anolyte awaytrom the observer, while the positlve signs represent the flow ofcatholyte toward the observer. .A packing piece 15 is then locatedadjacent the late 14 and then a porous diaphragm 16. Ae next packingpiece is shown with its construction exactly reversed from that of 15.Likewise the plate 18 is in totally reversed disposition or formation tothe plate 14 and similarly the packing piece 19 is the reversal of thepacking piece 17, the diaphragm 20 the reversal of thediaphragm 16 andthe packing piece 21 the reversal of the packing piece 15. It will beunderstood that this arrangement ma be also repeated within the limitsdesire Moreover the arrowshown in a downward direction re resentsdiagrammaticall the direction of ow of the anode while t e upwardlydirected arrow indicates diagrammatically the direction of low of thecatholyte which it will be observed is in counterdirection to the iiowof anolyte.

I am aware that apparatus embodying bipolar late electrodes for use inrefining metals. y electrolysis has been proposed heretofore and inwhich such electrodes have 'been arranged in pack lformation immersed inelectrolyte, it bein observed however that the electrodes actua ly takepart in an exchan e action during the process which is comme y t knownas rening.

What I claim and desire to secure by Letters Patent is Y 1. A` bi-polarelectrolytic cell for electrodeposition of metals from solutions oftheir salts consisting of a'number of closcl posi ,tioned sheet metalelectrodes, each aving adjacent to one of the horizontal margins thereofapertures therethrough, a gasket `shaped to encompass `the margin of thesheet for as many p polar filter press type for the de stion of metals,comprising a plurality o apertured` anode-and cathode plates which areseparated by marglnally located gaskets, a diaphragm between the gasketshaving mar al aper- .m

tures, the parts constituting a ce 1 in which the gaskets, diaphragmsand the plates have registerin apertures which admit of and efect simutanenously a vertical and lateral flow of the electrolyte through suchcells.

In witness whereof I aiiix my signature.

ROBERT EDGEWORTH-JOHNSTONE.

metal electrode, a porous diaphragm having apertures adjacent to one ofits longer or side edges, a gasket provided with an interior space andwith an opening positioned adjacent toits lower corner, the partsconstituting one element of a cell, the adjacent element of the cellconsisting of similar elements in reversed order.

2. In anelectrolytic apparatus ofthe bi-

